The story begins on April Fools' Day as Homer is playing pranks on Bart throughout the day. Bart, angered by the numerous tricks he has fallen for, attempts to get revenge by shaking up a beer in a paint shaker. When Homer opens the beer, it results in a massive explosion that puts him in the hospital, paralyzed and placed in a wheelchair. While everyone waits for Homer to get well, the family remembers surviving similar hardships, shown in the form of clips from past episodes.
At the hospital, Homer sees a candy machine and, while trying to get chocolate, accidentally tips it on himself. The machine crushes him and puts him in a coma. After that, Mr. Burns then tries to pull the plug on Homer's life support system to keep from having to pay for Homer's health insurance. As Homer lies unconscious in the hospital bed, Bart tearfully confesses that he was the one who put him in the hospital with his shaken beer can prank. Having heard this, Homer comes out of the coma and ends up strangling Bart for his prank. Despite this, Marge and the others are happy that Homer is finally well. The episode ends with Homer, still under the assumption that it is April Fools' Day, trying to fool the family by saying he is taking them to Hawaii. However, Bart, Lisa, and Marge tell Homer that the current date is May 16, that Homer was in a coma for 7 weeks, and that he lost 5% of his brain as a result. The family laughs it off even though Homer's not sure why he is laughing.